Police are failing to record an estimated 20 per cent of crimes, according to a damning watchdog report published today in the wake of allegations that officers fiddle the figures.

The under-recording by forces in England and Wales is the equivalent of almost three quarters of a million offences and would put police crime figures for last year on 4.4 million rather than the 3.7 million published last week.

Serious sexual crimes, including at least 14 rapes, were not recorded, according to the interim findings of the most extensive audit of police crime figures, which included the Metropolitan and Greater